All terrain vehicle

ABSTRACT

Various embodiments of a saddle type vehicle are described. Configurations are shown in which the engine is located more towards the rear of the vehicle and in which the fuel tank extends generally vertically beneath the steering member. A radiator may also be located at a rear portion of the vehicle, rearwardly of the engine. A front storage compartment is also provided in the front portion of the vehicle. The resulting vehicle has improved access and storage capabilities and also has a lower center of gravity.

This application is a continuation application of U.S. application Ser.No. 09/057,652 now U.S. Pat. No. 6,523,634, entitled “ALL TERRAINVEHICLE”, which was filed on Apr. 9, 1998 and is incorporated herein byreference in its entirety.

FIELD OF THE INVENTION

The present invention relates to the field of all terrain vehicles. Moreparticularly, the invention relates to a saddle type vehicle comprisingimproved features.

BACKGROUND TO THE INVENTION

During the last decade or so, the popularity of all terrain vehicles(also referred to as “ATV's”) has greatly increased. These types ofvehicles are indeed very practical and versatile as they may be used forwork or leisure related tasks. By virtue of their relatively compactnature, their great mobility and traction, they are capable ofcirculating in all sorts of surfaces, from the common back yard to themore challenging wood trail. Since they are also fairly powerful, allterrain vehicles are also used to pull or push various objects such as atrailer or a snow-plow.

Initially, these types of vehicle comprised a steerable front wheel andtwo driving rear wheels connected to an engine. Such three-wheeledvehicles were however very unstable and had a tendency to overturn andcause serious injuries, if not death, to the user. In order to increasestability, the three-wheel base was therefore changed to a four-wheelbase.

FIG. 1 illustrates an embodiment of a saddle-type vehicle typicallyfound in the prior art. Such a vehicle comprises four wheels mounted toa frame, the front ones being steerable. A fuel tank and a seat aredisposed on an upper portion of the frame. The engine, which representsone of the heaviest components of the vehicle, is typically mounted in acentral portion of the vehicle, usually below the fuel tank and a frontportion of the seat. The engine location is specifically chosen toensure a proper weight distribution. If the engine is water cooled, aradiator will be provided in front of the engine. Examples of suchvehicles are described in more details in U.S. Pat. No. 4,757,872,issued on Jul. 19, 1988 and naming Inomata as inventor and in U.S. Pat.No. 5,515,940, issued on May 14, 1996 and naming Shichinohe et al. asinventors.

While such a configuration provides vehicles with performance levelsthat are more than adequate, there are nonetheless many disadvantagesassociated with it.

In order to sit properly and drive astride, the user must “mount” thevehicle, i.e. he or she must raise one leg over the fuel tank, seat orrear portion of the vehicle in order to sit on or get off the vehicle.Thus, one of the main disadvantages is that access to and from thevehicle can be somewhat challenging. Because of this, some persons tendto drive while assuming a “side-saddle” position and changing gearsusing a rope tied to the gear lever. This is impractical.

Another inconvenience associated with the location of the fuel tank isthat it renders engine access more difficult since there is little spacebetween the cylinder head of the engine and the tank. This isimpractical during repair since the fuel tank must be removed. Since thefuel tank is also a relatively heavy component and since it is locatedon the upper portion of the frame, the above-mentioned configurationalso has the disadvantage of creating a relatively high center ofgravity.

The location of the radiator in front of the engine also has variousdisadvantages. Since, during normal use, the vehicle travels mostly inthe forward direction, the front-located radiator is more exposed to thepossibility of being pierced by a branch or the like or being obstructedby mud. In order to compensate for this, it may be possible to cover theradiator with a protective member but this reduces the amount of airreaching the radiator thereby reducing its cooling efficiency. Thislocation of the radiator is also an ineffective use of valuable space.

The configuration referred to above also leaves very little room toaccommodate storage compartments or additional accessories, especiallyin the front portion of the vehicle.

OBJECTS AND SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide asaddle-type vehicle having an improved frame and improved accessfeatures.

It is a further object of the present invention to provide a saddle-typevehicle having a relatively lower center of gravity.

It is yet another object of the present invention to provide a vehiclehaving improved storage capabilities.

As embodied and broadly described herein, the invention provides asaddle-type vehicle comprising a frame, a pair of front wheels suspendedfrom a front portion of the frame, a pair of rear wheels suspended froma rear portion of the frame, a power unit mounted on the frame, atransmission allowing the power unit to transmit power to either one ofthe front or rear pairs of wheels, a seat located in between the frontand rear pairs of wheels, wherein a main portion of the power unit isdisposed beneath the seat.

In a preferred embodiment, a main portion of the transmission is alsodisposed beneath the seat and the power unit comprises a crankshaft anda transmission shaft extending in a running direction of the vehicle,and a rear drive shaft is connected to a rear end of the transmissionshaft on one end and to a rear differential on the other end to allowthe power unit to transmit power to the pair of rear wheels.

In the context of the present specification, the term “differential”should be interpreted as meaning any types of device that is capable ofimparting a rotational movement to a pair of wheels from a drivingshaft, whether or not it permits one wheel to revolve faster than theother one. This includes any type of gearing such as ring and piniongearing, spiral gearing, hypoid gearing, worm gearing or the like. Thisalso includes any types of viscous coupling.

In another preferred embodiment, the vehicle comprises a front driveshaft connected to a front end of the transmission shaft on one end andto a front differential on the other end to allow the power unit totransmit power to the pair of front wheels.

In another embodiment, the power is transmitted to either one of thefront or rear pairs of wheels through a drive chain and sprocketarrangement.

In a preferred variant, the seat is pivotal connected to the frame, theseat being moveable between a first position whereby the driver maydrive the vehicle and a second position whereby the driver may accessthe power unit. The seat preferably comprises a pommel located at afront portion thereof and is most preferably removably connected to theframe.

As embodied and broadly described herein, the invention also provides asaddle-type vehicle comprising a frame, a pair of front wheelscomprising first and second wheels suspended from a front portion of theframe, a pair of rear wheels comprising third and fourth wheelssuspended from a rear portion of the frame, the first and second wheelsdefining a first transversal axis and the third and fourth wheelsdefining a second transversal axis, a power unit mounted on the frame, atransmission allowing the power unit to transmit power to either one ofthe front or rear pairs of wheels, a seat located in between the frontand rear pairs of wheels, wherein a main portion of the power unit islocated between the second transversal axis and an imaginary axislocated at a median point between the first and second transversal axis.

In a preferred embodiment, the power unit comprises a crankshaft and atransmission shaft extending in a running direction of the vehicle, andwherein a rear drive shaft is connected to a rear end of thetransmission shaft on one end and to a rear differential on the otherend to allow the power unit to transmit power to the pair of rearwheels. Most preferably, the vehicle also comprises a front drive shaftconnected to a front end of the transmission shaft on one end and to afront differential on the other end to allow the power unit to transmitpower to the pair of front wheels.

In yet another aspect, the invention provides a saddle-type vehiclecomprising a frame, a pair of front wheels suspended from a frontportion of the frame, a pair of rear wheels suspended from a rearportion of the frame, a power unit mounted on the frame, a fuel tank, atransmission allowing the power unit to transmit power to either one ofthe front or rear pairs of wheels, a seat located in between the frontand rear pairs of wheels, wherein a main portion of the fuel tank isdisposed substantially below the horizontal plane defined by theuppermost portion of the seat. Preferably a main portion of the powerunit and of the transmission are disposed beneath the seat.

As embodied and broadly described herein, the invention further providesa saddle-type vehicle comprising a frame, a pair of front wheelssuspended from a front portion of the frame, a pair of rear wheelssuspended from a rear portion of the frame, a steering member connectedto a steering mechanism for steering the front wheels, a power unitmounted on the frame, a fuel tank, a transmission allowing the powerunit to transmit power to either one of the front or rear pairs ofwheels, a seat located in between the front and rear pairs of wheels,wherein a main portion of the fuel tank is located beneath the steeringmember. Preferably, a main portion of the fuel tank is also disposedsubstantially below the horizontal plane defined by the uppermostportion of said seat and is disposed vertically.

In a further aspect, the invention also provides a saddle-type vehiclecomprising a frame, a pair of front wheels suspended from a frontportion of the frame, a pair of rear wheels suspended from a rearportion of the frame, a steering member connected to a steeringmechanism for steering the front wheels, a seat located in between thefront and rear pairs of wheels, a power unit mounted on the frame andhaving a main portion thereof being disposed beneath the seat, a fueltank located beneath the steering member, a transmission allowing thepower unit to transmit power to either one of the front or rear pairs ofwheels, the vehicle further comprising an open area located between thefuel tank and the power unit, the open area providing easier access toand from the vehicle. The vehicle may comprise an additional storagecontainer removably secured in the open area and the additional storagecontainer may be an additional fuel tank.

As embodied and broadly described herein, the invention provides asaddle-type vehicle comprising a frame, a pair of front wheelscomprising first and second wheels suspended from a front portion of theframe, a pair of rear wheels comprising third and fourth wheelssuspended from a rear portion of the frame, a water cooled enginemounted on the frame, a transmission allowing the engine to transmitpower to either one of the front or rear pairs of wheels, a seat locatedin between the front and rear pairs of wheels, the vehicle furthercomprising a radiator located at the rear portion of the frame.

Preferably, the radiator is located between the third and fourth wheels,behind the seat and is angled generally toward the seat.

In a preferred embodiment, the radiator further comprises a cooling fandisposed behind the radiator and the vehicle also comprises aventilation opening for conveying cooling air to the radiator. Mostpreferably, the vehicle comprises at least two ventilation openingslocated above the third and fourth wheels respectively.

In another aspect of this invention, there is provided a saddle-typevehicle comprising a frame, a pair of front wheels suspended from afront portion of the frame, a pair of rear wheels suspended from a rearportion of the frame, a steering member connected to a steeringmechanism for steering the front wheels, a seat located in between thefront and rear pairs of wheels, a power unit mounted on the frame, afuel tank, a transmission allowing the power unit to transmit power toeither one of the front or rear pairs of wheels, the vehicle furthercomprising a storage compartment located forward of the steering member.

The invention also provides a saddle-type vehicle comprising a frame, apair of front wheels suspended from a front portion of the frame, a pairof rear wheels suspended from a rear portion of the frame, a steeringmember connected to a steering mechanism for steering the front wheels,a seat located in between the front and rear pairs of wheels, a powerunit mounted on the frame and having a main portion thereof beingdisposed beneath the seat, a fuel tank located beneath the steeringmember, a transmission allowing the power unit to transmit power toeither one of the front or rear pairs of wheels, the vehicle furthercomprising an open area located between the fuel tank and the powerunit, the open area providing easier access to and from the vehicle, thevehicle further comprising a storage compartment located forward of thesteering member.

The saddle-type vehicle of the present invention offers many advantagesover the prior art. By moving the engine rearwardly and by preferablymoving the fuel tank forward and downwardly, there is provided asaddle-type vehicle having a open area that allows easier access to thevehicle. This also provides the user with the option of maximizing thisarea by adding an additional storage container, such as a additionalfuel tank. The resulting vehicle also has a lower center of gravity.

The improved radiator location also reduces the probabilities of itbeing damaged while freeing an important amount of space in the frontportion of the vehicle that may be used an additional larger storagearea.

Other objects and features of the invention will become apparent byreference to the following specification and to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The following is a description by way of a preferred embodiment,reference being made to the following drawings, in which:

FIG. 1 is a side view of a saddle-type vehicle according to the priorart;

FIG. 2 is a perspective view of a saddle-type vehicle according to thepresent invention;

FIG. 3 is a side view of a vehicle according to the present inventionillustrating more particularly the frame and the power transmissionsystem;

FIG. 4 is a perspective view of a frame;

FIG. 4a is a side view of a frame;

FIG. 5 is a top plan view of a vehicle according to the presentinvention illustrating more particularly the frame and the powertransmission system;

FIG. 6 is a top plan view of a vehicle according to the presentinvention;

FIG. 7 is a side view of the vehicle illustrated in FIG. 2;

FIG. 8 is a side view illustrating the front hatch in an open positionand the seat in an engine access position;

FIG. 9 is a perspective view of a seat and mounting brackets thereof;

FIG. 10 is a perspective view of a rear portion of a vehicle accordingto the present invention illustrating the position of the radiator;

FIG. 11 is a perspective view of a portion of a seat and rear fendersillustrating the ventilation openings;

FIG. 12 is an exploded view of the rear fenders and ventilation channelscover;

FIG. 13 is a perspective view of a front storage compartment with thehatch in an open position;

FIG. 14 is a perspective partial view of the steering member,instrumentation panel and fuel tank;

FIG. 15 is a perspective view of an additional storage container;

FIGS. 16 and 17 are side views of a vehicle according to the presentinvention comprising an additional container.

DESCRIPTION OF A PREFERRED EMBODIMENT

FIG. 1 illustrates a saddle-type vehicle 2 conventionally found in theprior art. Such a vehicle comprises four wheels 10 mounted to a frame12, the front ones being steerable through a steering member 14connected to a steering mechanism (not shown). The frame 12 comprises anupper member 12′ extending on an upper portion of the vehicle above thepower unit and a lower member 12″ extending on a lower portion thereof.A fuel tank 16 and a seat 18 are disposed on an upper portion of theframe 12. The power unit 20, which represents one of the heaviestcomponents of the vehicle, is typically mounted in a central portion ofthe vehicle, usually below the fuel tank 16 and a front portion of theseat 18. If the power unit is a water cooled engine, a radiator will beprovided in front of the engine.

A preferred embodiment of the saddle-type vehicle according to thepresent invention is generally illustrated in FIGS. 2 and 3.

Referring now to FIGS. 3 and 4, the vehicle, generally referred to at30, comprises a main frame portion 34 and a secondary frame portion 38that is attached to the main frame portion 34 at attachment points 42and 46 which may consist of typical brackets. The front area of the mainframe portion comprises all the attachments that are necessary toreceive and accommodate the upper and lower front suspension arms, thefront differential, steering linkage and other typical componentsincluding a front bumper 35. The rear area of the main frame portionextends upwardly and terminates by the two upper brackets 46 and the twolower brackets 42. The main frame portion also comprises openings 41 forpivotally attaching rear swing arms as described below and brackets 44for mounting the power unit. The upper and lower brackets 46 and 42 areused to attach the secondary frame portion 38 to the main frame portion34 as explained before. The upper brackets 46 are also used to receiveand attach the upper end of the rear shock absorbers 50 to the mainframe portion 34. Both the main and the secondary frame portions are ofconventional construction and may be constructed from tubular or stampedmembers.

The provision of a main and of a secondary frame portions providevarious advantages. First, the inventors have realized that it may bemore efficient on an assembly line to manufacture a frame in two partsrather than as a single component when using conventional tooling. Incontrast with the vehicles of the prior art, the main frame portion ofthe vehicle of the present invention does not comprise an upper memberthat is located above the power unit (referred to at 12′ in FIG. 1) andthat prevents the frame from bending. As a result, the main frameportion of the vehicle of the present invention must be capable ofwithstanding the same amount of stress that is imparted on aconventional frame. Typically, this will be achieved by manufacturingthe main frame portion from a material having a higher creep resistenceor by using larger members. Reinforcement members, such as 36 and 7 mayalso be provided to assist the main frame portion in maintaining itsstructural integrity. Since the main frame portion is intended toaccommodate the majority of the stress imparted to the vehicle, thesecondary frame portion may as a result be manufactured using a smallerstructure or from a less expensive material. Apart from reducing costs,such an embodiment also has the advantage of providing a lightervehicle. The person skilled in the art will however realize that this isonly a preferred embodiment and that the objects of the presentinvention may be achieved using a unitary frame structure.

A pair of front wheels comprising a first wheel 58 and a second wheel 60is suspended from the front area of the main frame portion. Moreparticularly, the vehicle comprises upper suspension arms 64 (FIG. 5)and lower suspension arms (not shown) that are pivotally attached to theframe at one end and to a steering knuckle via ball joints at the otherend. The steering knuckles each comprise a spindle adapted to receive awheel and its bearings. The steering knuckles are connected to asteering member 100 through a conventional steering linkage or mechanismso as to provide steerable front wheels. A pair of front shockabsorbers/coil springs assemblies 70 connected to the frame at bracket39 at one end and to the upper suspension arms at the other end are alsoprovided.

If the vehicle is intended to be of the four wheel drive type, power istransmitted from the power unit to the front wheels through aconventional mechanism comprising front axles 68 and a frontdifferential 72 that is coupled to the power unit via a front drivingshaft 76.

A pair of rear wheels comprising a third wheel 80 and a fourth wheel 82is suspended from the rear area of the main frame portion. Moreparticularly, the vehicle comprises rear swing arms 84 that arepivotally connected to the main frame portion at one end and to the rearaxle casing 86 at the other end. A pair of rear shock absorbers/coilspring assemblies 50 connected to the main frame portion on one end andto the rear axle casing 86 on the other end are also provided.Alternatively, a single shock absorber/coil spring assembly could beused at the rear, provided it is located in a generally median location.

Power is transmitted from the power unit to the rear wheels through aconventional mechanism comprising a rear differential 90 that is coupledto a rear driving shaft 94 at one end and to a rear axle located in rearaxle casing 86 at the other end. The rear driving shaft is located in asuitable housing. In a preferred embodiment, one of the rear swing arms84 may serve as a housing for the rear driving shaft. In order toaccommodate the angular movement of the rear swing arm, a universaljoint is provided at a suitable location, preferably near the powerunit.

While the preferred embodiment has been described using drive shafts totransmit power from the power unit to the front or rear pairs of wheels,other types of power transmission means may be provided. For example,the drive shafts could be replaced by suitable drive chain and sprocketarrangement.

As shown more particularly in FIG. 14, an instrument board 210 isprovided on the steering member 100 and comprises the usual indicatorssuch as speedometer, odometer, indicator lights, etc. A device forelectrically shifting gears 214 may also be provided if the vehicle isequipped with a semi-automatic transmission. A main gear lever 212, forselectively engaging either one of a Park, Neutral, High, Low or Reverseposition is also conveniently located near the steering linkage.

The vehicle is also provided with a conventional braking mechanism whichmay comprise disk or drum brakes. The brakes may be hydraulically ormechanically activated.

As shown more particularly in FIGS. 2, 6 and 7, the vehicle alsocomprises front fenders 104 attached to the frame and defining frontwheelhouses 108. The front portion of the vehicle also includes a frontgrille 106 and headlamps 107 and may comprise a front rack 110. A frontstorage compartment 180 (FIG. 3) is also provided at the front portionof the vehicle, in front of the steering member 100. Rear fenders 112are also attached to the frame. The rear fenders may also comprisesplash guards 120 and a rear rack 124. As shown more particularly inFIG. 10, the rear portion of the vehicle may also comprise reflectivetapes 132 and a rear lamp 134. The rear fenders also compriseventilation openings 130 (FIGS. 11 and 12), the purpose of which will bedescribed hereinafter. Front and rear bumpers 35 and 128 are alsorespectively secured to the main and secondary frame portions 34 and 38.

Full foot rests 54 are also provided on each sides of the vehicle, inbetween the front and rear fenders. The foot rests 54 may accommodate agear shift lever (if the vehicle does not have a semi-automatictransmission) and brake lever (not shown). The provision of full footrests provides increased comfort in contrast with the typical foot pegsince the weight is distributed over the entire bottom surface of thefoot.

A saddle-type seat 140 is also removably secured to the frame usinggenerally U-shaped brackets 142 (FIGS. 8 and 9) or 143 (FIG. 4) that aresecurely fixed to the frame. As shown in FIG. 9, the seat comprises abase portion 146 made from a suitable material such as plastic. The baseportion 146 is shaped so as to surround and enclose the power unitthereby enhancing the aesthetics of the vehicle when the seat is in aclosed position as shown in FIG. 7. The upper portion of the seat isprovided with a suitable padding material and a pommel 141 is disposedat a front portion thereof to improve comfort. A support member 144 issecured to the base 146 and is adapted to engage bracket 142 or 143 tosecure the seat in place. A locking device 148 maintains the seat in aclosed position wherein the driver may drive the vehicle.

As shown in FIG. 8, the engine compartment of the vehicle is readilyaccessible by simply pivoting and/or removing the seat. In order toremove the seat, the user unlocks the locking device 148, pivots theseat upwardly and thereafter slides the seat rearwardly until thesupport member 144 clears the upper portions of the brackets 142 or 143.

Since the power unit is enclosed beneath the seat 140, ventilationopenings 147 are preferably provided in the base portion 146 of the seatin order to ensure proper ventilation of the engine compartment. Theventilation openings 147 preferably also extend to the side of the seatsince accessories, which would block the openings, may be provided infront of the base portion of the seat as shown in FIGS. 16 and 17.

A suitable type of power unit for use in the context of the presentinvention is preferably capable of simultaneously driving the front andrear wheels, although rear or front wheel drive vehicles may also becontemplated. A preferred type of power unit includes an engine and atransmission integrally joined to one another. The crankshaft, main andsecondary shafts and output or transmission shaft all extend in the samedirection which preferably corresponds to the longitudinal direction ofthe vehicle. In a preferred embodiment, the transmission shaft isconnected to the rear driving shaft 94 at one end and, if the vehicle isof the four wheel drive type, is also connected to the front drivingshaft 76 at the other end. The power unit comprises all the necessarycomponents such as a carburetor 152, an exhaust pipe 154, a muffler 156,an air filter 158 having an air intake, and a battery 161 (FIG. 5).

The basic internal construction of the power unit will not be describedin details as it will be readily apparent to the person skilled in theart that the invention may be practiced with any suitable types of powerunits.

In contrast with the prior art, where the power unit is mounted in acentral portion of the vehicle, the power unit of the vehicle of thepresent invention is mounted more towards the rear portion of thevehicle.

In a first preferred embodiment, the position of the power unit may bedefined in relation to various transversal axis. More specifically, thelocation of the power unit 150 may be defined in relation to animaginary axis x³ that is located at a median point between a firsttransversal axis x¹ defined by the front wheels 58 and 60 and a secondtransversal axis x² defined by the rear wheels 80 and 82. Moreparticularly, in this embodiment, a main portion of the power unit islocated in between the median axis x³ and the second axis x².

If, in another embodiment, the vehicle is provided with two pairs ofrear wheels, for a total of six wheels, the second axis x² will definedby the two foremost rear wheels.

In another embodiment, the location of the power unit may be defined inrelation to the seat. Thus, as shown in FIGS. 3 and 8 and in contrastwith the prior art, the present invention may be characterized by avehicle in which a main portion of the power unit 150 is disposedbeneath the seat 140.

Another aspect of the invention resides in the location of the fuel tank160. Since a full fuel tank represents a relatively heavy component ofthe vehicle, its location is important to ensure proper weightdistribution and proper balance of the vehicle. As shown in FIGS. 3, 6and 14, in one embodiment, the fuel tank, that comprises a fuel cap 162and a fuel gage 164, extends vertically beneath the steering member 100and more particularly, substantially below the horizontal plane z′defined by the uppermost portion of the seat 140.

The location of the fuel tank at this specific area provides manybenefits. First, by providing a tank that extends in the verticaldirection, it is possible to concentrate an important amount of weightin the lower portion of the vehicle thereby lowering its center ofgravity.

By moving the fuel tank 160 from an upper portion of the frame to anarea located generally beneath the steering member 100, there isprovided an open area 200, between the fuel tank 160 and the power unit150. This open area 200 facilitates access to and from the vehicle asthe driver does not have to raise his leg above the level of the fueltank, seat or rear portion of the vehicle. The open area also providesspace to secure additional storage containers.

The person skilled in the art will realize that some objects of thepresent invention may be achieved by locating the fuel tank at an areaother than beneath the steering member 100. For example, the fuel tankcould be located at a front portion of the vehicle, and could surroundthe steering linkage. The location of the fuel tank will therefore bedictated by balance and security considerations.

If the power unit is a water-cooled engine, the vehicle may comprise aradiator 170. In the preferred embodiment, the radiator is locatedbehind the engine at the rear area of the secondary frame portion. Theradiator may be fixed to the frame by securing it to bracket 47 (FIG.4). As shown more particularly in FIG. 10, the radiator is preferablyinclined forward and upwardly towards the seat of the vehicle andcomprises a grille (not shown) and a schroud 174 protecting the grille.A cooling fan 172 is mounted within the shroud in a conventional manner.

The provision of a radiator at the rear portion provides increasedprotection by limiting its exposure. Since, during normal operation, thevehicle travels mostly in the forward direction, the possibilities ofthe rearwardly located radiator being pierced by a branch or the likeare therefore substantially reduced. The location of the radiator at therear portion of the vehicle also permits to make a more efficient use ofthe space in the front portion thereof and provides room to moreefficiently locate the fuel tank as explained above.

Referring now to FIGS. 11 and 12, there are provided forward facingventilation openings 130 for conveying air to the radiator 170. In orderto convey the cooling air, ventilating channels 190 are defined withinthe rear fenders 112 as shown more particularly in FIG. 12. A coverportion 113 covers the channel and protecting grilles 192 are providedto prevent debris from entering and blocking the ventilating channels.

By locating the radiator at a rear portion of the vehicle, the inventorswere also capable of maximizing the amount of space at the front of thevehicle. By providing a rear radiator, the inventors were capable ofproviding a front storage compartment 180 at a front portion of thevehicle, forward of the steering member (FIG. 3). The storagecompartment comprises a hatch 184 that is pivotally secured to thevehicle and that is preferably removable. The front storage compartmentmay be provided with a waterproof removable container 185 that may beused as a cooler or that may be used as a tank to keep the catch of theday if the user is an avid fisherman as an example. Absent such frontstorage compartment, the driver would have to secure any objects to thefront or rear racks 110 or 124 by using ropes or the like. This is timeconsuming.

A plurality of additional storage containers or accessories adapted tobe inserted into the open area 200 may be provided. An example of anadditional storage container is illustrated in FIG. 15 and comprises acontainer portion 201 and a hatch 202. FIG. 16 illustrates thepossibility of providing an additional fuel tank 204 that is secured tothe vehicle via mounting brackets 206. Evidently, this type ofadditional fuel tank will have to respect all applicable security andliability requirements before being installed on the vehicle. Anotherpossible embodiment concerning a smaller tank 208 is shown in FIG. 17.

Other types of accessories, such as a winch 210, may also be provided,preferably within the front portion of the vehicle underneath thestorage compartment 180.

The above description of a preferred embodiment should not beinterpreted in any limiting manner since variations and refinements arepossible which are within the spirit and scope of the present invention.The scope of the invention is defined in the appended claims and theirequivalents.

The embodiments of the invention for which an exclusive property orprivilege is claimed are defined as follows:
 1. An all terrain vehiclecomprising a frame, a pair of all terrain front wheels suspended from afront suspension connected to said frame, a pair of all terrain rearwheels suspended from a rear suspension connected to said frame, a pairof front fenders positioned above the pair of all terrain front wheels,a power unit mounted on said frame, a transmission allowing said powerunit to transmit power to at least one of said front and rear pairs ofwheels, a straddle seat located in between a first transversal axisdefined by the pair of all terrain front wheels and a second transversalaxis defined by the pair of all terrain rear wheels, said straddle seathaving a forwardly facing portion including an exposed, substantiallyvertical portion and defining in part an open step through areaextending below an uppermost portion of the pair of front fenders andforward of the straddle seat, to provide access to and from the vehicle,wherein a main portion of said power unit is disposed beneath saidstraddle seat.
 2. The vehicle of claim 1, wherein a main portion of saidtransmission is disposed beneath said straddle seat.
 3. The vehicle ofclaim 1, wherein said power unit comprises a crankshaft and atransmission shaft extending in a running direction of said vehicle, andwherein a rear drive shaft is connected to a rear end of saidtransmission shaft on one end and to a rear differential on the otherend to allow said power unit to transmit power to said pair of allterrain rear wheels.
 4. The vehicle of claim 1, further comprising afront drive shaft connected to a front end of said transmission shaft onone end and to a front differential on the other end to allow said powerunit to transmit power to said pair of all terrain front wheels.
 5. Thevehicle of claim 1, wherein said straddle seat comprises a pommellocated at a front portion thereof.
 6. The vehicle of claim 1, whereinsaid power is transmitted to either one of said front and rear pairs ofwheels through a drive chain and sprocket arrangement.
 7. The vehicle ofclaim 1, wherein said straddle seat is pivotably connected to saidframe, said straddle seat being moveable between a first positionwhereby the driver may drive the vehicle and a second position wherebythe driver may access the power unit.
 8. The vehicle of claim 1, whereinsaid straddle seat is removably connected to the frame.
 9. The vehicleof claim 1, wherein the open step through area is fixed with respect toat least one of the front fenders and the power unit.